LED display screen is widely used in public places. Most of the large screens in the square are LED screens, which have the characteristics of long service life and low energy consumption. If the design of LED display screen is inappropriate, it will affect the future use. This paper summarizes eight factors, which should be paid attention to in the design of LED screen:1. Heat dissipation designWhen the LED works, it will generate heat. Too high temperature will affect the attenuation speed and stability of the LED. Therefore, the heat dissipation design of PCB and the ventilation and heat dissipation design of the box will affect the performance of the LED.
2. Mixed lampLEDs with different brightness levels of the same color need to be mixed, or inserted according to the lamp insertion diagram designed according to the discrete law, so as to ensure the consistency of the brightness of each color on the whole screen. If there is a problem in this process, the local brightness of the large screen will be inconsistent, which will directly affect the display effect of the LED large screen.3. Design current value
The nominal current of LED is 20mA. Generally, it is recommended that the maximum use current should not exceed 80% of the nominal value. Especially for large screens with small point spacing, the current value should be reduced due to poor heat dissipation conditions. According to experience, due to the inconsistency of the attenuation speed of red, green and blue LEDs, the current value of blue and green LEDs should be reduced to maintain the consistency of white balance after long-term use of the large screen.4. Driving circuit design
The layout of the driving circuit board and driving IC on the large screen module will also affect the brightness of the LED. Because the driving IC output current is transmitted too far on the PCB, the voltage drop in the transmission path will be too large, affecting the normal working voltage of the LED and reducing its brightness. We often find that the LED brightness around the large screen module is lower than that in the middle, which is why. Therefore, to ensure the consistency of large screen brightness, it is necessary to design the distribution diagram of driving circuit.
5. Control the verticality of the lampFor in-line led, there should be enough technology to ensure that the LED is perpendicular to the PCB when passing through the furnace. Any deviation will affect the brightness consistency of the set led, and color blocks with inconsistent brightness will appear.6. False soldering control
When the LED on the large LED screen is not lit, there is often more than 50% probability that it is caused by various types of false soldering, such as LED pin false soldering, IC pin false soldering, pin and bus false soldering, etc. The improvement of these problems needs to strictly improve the process and strengthen the quality inspection. The vibration test before leaving the factory is also a good inspection method.7. Over wave soldering temperature and time
The temperature and furnace passing time of wave front welding must be strictly controlled. It is recommended that the preheating temperature is 100 5 and the maximum temperature shall not exceed 120 , and the preheating temperature rise shall be stable. The welding temperature is 245 5 , and the welding time is recommended not to exceed 3 seconds. Do not vibrate or impact the LED after furnace passing until it returns to normal temperature. The temperature parameters of wave soldering machine shall be detected regularly, which is determined by the characteristics of LED. Overheating or fluctuating temperature will directly damage led or cause hidden dangers of LED quality, especially for small-size circular and Oval LEDs such as 3mm.
8. AntistaticThe LED large screen assembly factory shall have good anti-static measures. Special anti-static ground, anti-static floor, anti-static soldering iron, anti-static table pad, anti-static ring, anti-static clothing, humidity control, equipment grounding (especially foot cutting machine) are the basic requirements, and should be tested regularly with an electrostatic instrument. For more information, please continue to visit the LED display quotation of the industry information channel of China logo network.